A common problem encountered in intravenous fluid administration is the infiltration of the fluids into tissues near the point of entry of the catheter into the veins or arteries (vascular system). Infiltration is often due to patient movement and disruption of the vein or artery at the site of insertion of the catheter. This may lead to discoloration, discomfort and tissue destruction as well as lack of delivery of the intravenous fluids or drugs into the patient's system. Many surgical procedures including amputation may be required when certain drugs or fluids infiltrate the patient's tissues, causing necrosis. Permanent disfigurement and/or disability may be the result.
There are a number of devices and methods for detection of tissue infiltration during intravenous administration of fluids. These detection techniques include the measurement of the skin temperature in potential infiltration areas. These devices use temperature sensors for continuous monitoring of the skin temperature near the intravenous catheter. When colder intravenous fluids accumulate in tissue from infiltration the skin temperature falls. (See, for example, U.S. Pat. No. 3,618,602) The sensitivity of this technique may be enhanced by heating the skin around the catheter site so that tissue infiltration causes a greater temperature change. (U.S. Pat. No. 4,010,749) These devices do not work well when the administered fluid is not colder than the patient's skin. Additionally, when enough fluid has infiltrated to cause a temperature shift, edema and necrosis may already have occurred.
The most common method for detecting infiltration is by monitoring fluid delivery by a pump. In its simplest form, the drop frequency is monitored in the delivery chamber and an alarm is sounded if fluid delivery stops or falls short of the desired amount. More sensitive techniques include various methods for measuring specific changes in fluid delivery pressure as an index of infiltration. (See U.S. Pat. No. 4,534,756). Once infiltration has occurred and the equilibrium is disturbed in the infiltrated tissue the back flow pressure rises thus signaling infiltration. These devices cannot measure the initial event of infiltration, however, and studies have shown that they are probably not sensitive enough to signal an infiltration early enough to prevent irreversible changes in the tissue.
Another detection technique relies on clinical parameters including patient pain and actual visual inspection, by hospital personnel, of the area surrounding the catheter for signs of infiltration. To be effective this technique requires continual monitoring by trained hospital personnel.
Many of the problems of the prior art devices are overcome by the present invention which employs the change in the electromagnetic radiation-altering properties of tissue when infiltration occurs. Such a system has not been used to detect tissue infiltration with intravenous fluids or drugs. Electromagnetic radiation reflectance, transmission and intensity measurements have been used in other systems to measure components of living tissue such as oxygenated hemoglobin in the bloodstream (U.S. Pat. No. 4,446,871), bilirubin in the blood serum (U.S. Pat. No. 4,029,085), blood oxygen saturation (U.S. Pat. No. 3,628,525) and perfusion of blood into body tissues following surgery (U.S. Pat. No. 4,608,990).
One object of this invention is to provide a sensitive device whereby infiltration of intravenous fluids into tissue may be detected soon after the infiltration begins to prevent disastrous edema or necrosis.
Another object of the invention is to provide a noninvasive method and device for detection of tissue infiltration of any intravenous fluid or drug regardless of delivery temperature or pH.
Another object of the invention is to provide a device whereby tissue infiltration of fluids is detected automatically and appropriate measures taken to prevent further infiltration without continuous monitoring of the patient by health care personnel.
Another object of the invention is to provide a device for notifying hospital personnel remote from the patient by triggering an alarm upon infiltration.
Another object of the invention is to use a signal output from the invention to create an audio and/or visual alarm and to stop the fluid delivery from independent electronic intravenous delivery devices such as infusion pumps, controllers, or gravity intravenous sets.
Another object of the invention is to provide a device for detection of tissue infiltration that will require no new skills on the part of nursing personnel.
Another object of the invention is to provide a device for detection of tissue infiltration that will not be triggered excessively by ambient noise, light and temperature changes nor by patient activities.
Still other objects and advantages of the invention will be apparent to those of skill in the art after reading the following description of the preferred embodiment.